JPS60247920A - Formation of deposited film - Google Patents

Abstract

PURPOSE:To form a deposited film using heat energy of a low level and at a high film forming speed by a method wherein the halogen derivative of a normal chain type or a branched-chain type Si hydride compound and a compound of H are heated. CONSTITUTION:After a supporter 2 is put on a supporting base 3 in a deposition chamber 1, the inside of the chamber is depressurized, a current is flowed to a heater 4, and raw material gas for formation of an a-Si film is sent in the deposition chamber 1. The raw material gas thereof is a chain type Si halide compound to be expressed by SinXmYl [X and Y are different halogen atoms respectively, (n) is the integer of 1-6, (m) and (l) are the integer of 1 or more respectively, and m+l=2n+2]. A gaseous atmosphere of the compound mentioned above and H is formed in the chamber, the compound and H are excited to be decomposed by utilizing heat energy, and a deposited film containing Si is formed on the substrate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a deposited film containing silicon, particularly amorphous silicon (hereinafter referred to as a-8i) useful as a light guide film, a semiconductor film, an insulator film, etc. The present invention relates to a preferred method of forming deposited films of polycrystalline silicon.

[Prior art]

Conventionally, the glow discharge deposition method and thermal energy deposition method using 8iH4 or S 1tHa as a raw material are known as methods for forming an a-8i deposited film. That is, these deposition methods use SiH4 or 8i2H as the raw material gas.
, electrical energy or thermal energy (excitation energy)
This is a method in which a deposited film of A-8i is formed on a support by decomposing the film, and the deposited film thus formed is used for various purposes such as a photoconductive film, a semiconductor film, or an insulating film.

However, in the glow discharge deposition method in which the deposited film is formed under high-power discharge, it is difficult to control reproducible and stable conditions such as not always achieving a uniform discharge distribution state, and furthermore, the film formation The effects of high-power discharge on the film inside the film are severe (it is difficult to ensure the uniformity of electrical and optical properties and quality stability of the formed film, the disturbance of the film surface during deposition, and the deposition Defects in the film are likely to occur.In particular, it is very difficult to form a deposited film of one thickness with uniform electrical and optical characteristics by this method.

On the other hand, the thermal energy deposition method also requires a high temperature of 400°C or higher, which limits the support materials that can be used, and in addition, useful bonded hydrogen atoms in the desired a-8i are separated. Since the number of fixed wheels increases, it is difficult to obtain desired characteristics.

Therefore, one way to solve these problems is to
A-8i low heat energy deposition method (thermal CVN) using silicon compounds other than SiH4 and Si2H6 as raw materials
is attracting attention.

This low-heat thermal energy deposition method uses low-temperature heating instead of glow discharge or high-temperature heating in the above-mentioned methods as excitation energy, and allows the production of a-8i deposited films at a low energy level. It is intended to enable implementation. In addition, the lower the temperature, the easier it is to uniformly heat the raw material gas, making it possible to form a high-quality film that maintains uniformity with lower energy consumption than the deposition method described above. Conditions can be easily controlled, stable reproducibility can be obtained, there is no need to heat the support to a high temperature, and there is also the advantage that selectivity to the support can be expanded.

[Purpose of the invention]

The present invention has been made in view of the above points, and uses low-level thermal energy as excitation energy to form a deposited film containing silicon atoms at a high deposition rate while maintaining high quality at a low energy level. It is an object of the present invention to provide a thermal energy deposition method that can form an image.

Another object of the present invention is to form a high-quality deposited film that ensures uniformity of electrical and optical characteristics and stability of quality even in the formation of a large-area, thick deposited film. The goal is to provide a method that can be used.

[Summary of the invention]

For the above purpose, the general formula: SinX
Chain halogenation represented by mYl (X and Y are each different halogen atoms, n is an integer from 1 to 6, 1m and l are each an integer of 1 or more, and s m + l '' 2n + 2) When a gaseous atmosphere of a silicon compound and hydrogen is formed and thermal energy is used, the compound and hydrogen are excited and decomposed by K, and silicon is deposited on the substrate.
This is achieved by a method for forming a deposited film characterized by forming a deposited film containing Con.

The chain halogenated silicon compound of the above general formula is a linear or branched chain silicon hydride compound (chain silane compound).
It is a halogen derivative of 8jnH2n+2, and is a compound that is easy to manufacture and has high stability. In the general formula,
X and Y each represent a different halogen atom selected from fluorine, chlorine, bromine and iodine. Set the value of n to 1~
The reason for limiting the number to 61C is that as n becomes larger, decomposition becomes easier, but it becomes difficult to vaporize, synthesis is difficult, and decomposition efficiency becomes worse.

Preferred examples of the chain halogenated silicon compounds of the general formula are:
They are listed below.

■F and CI! Compound containing: SiFmCl! t-m (m is an integer from 1 to 3), 3i2
FmCI! a-m (m is an integer from 1 to 5), St 3i
mCI! s -rn (" is an integer from 1 to 7), 8'4F
mCI! to-m (m is an integer from 1 to 9), ■F and Br
Compounds containing: 8tFmBr4-m (rn is an integer of 1 to 3), s'zF
'mBr6-m (m is an integer from 1 to 5), Si3FmB
r8-m (" is an integer from 1 to 7), 5t4F'm13r
lO-m (m is an integer from 1 to 9).

■CI! Compounds containing and Br: 8iC/mBr4-m (m is an integer of 1 to 3), 5t2
C1! mBrs-m (" is an integer from 1 to 5), 5i3e/
mBr5-m (" is an integer from 1 to 7), 8i4C/mB
r10-m (" is an integer from 1 to 9), ■ Compound containing F and I: 8'Fm 4-m (" is an integer from 1 to 3), Si2Fm
I6-m (m is an integer from 1 to 5).

Among the above-mentioned compounds (1) to (2), the most preferred specific examples include the following compounds. '(1) 8iF3C
/, (215iF2C12, (31StF3C/, ψ1
si2FcI! 5, (5) Sl zF2 C14, (
6) 5i2F3C/s, (7) 5i2F4Clz
, (8) 8i2FsC/s (9) st, F7c
I! , (115i3F', Cz2, (11) 5i3F
5CA'a, 035iFsBrsQ38iF2Br2,
Q4) 8iFBr3, (Li28i2F5Br.

(te 5i2F4Br2 % α7) 8i2F3B
r3, αQ 8iC/3Br.

(tl 8iCI!2Br2, QOS 1(JBr 3
, (2υsip, Eng.

0ri ail", I.

In the present invention, by forming a gaseous atmosphere of the chain halogenated silicon compound of the general formula and hydrogen in the chamber, the hydrogen radicals generated during the excitation/decomposition reaction increase the efficiency of the reaction. Moreover, hydrogen is incorporated into the deposited film that is formed, which serves to reduce defects in the Si-bonded structure. In addition, the chain-like []) rogenated silicon compound of the general formula has six, 5ix2.5ix in the decomposition process.
ss 8'2X3 s '3'2X4 s S '8X
4 s S' 3X5 s 8 'Y 5SIY2,
5LY3.812Y3, 812Y4, St 3Y
4, si3Y5.5ixy, 5txy2.5
i2xy2.5i2xy3.5i3xy3.5i3X2
Radicals such as Y2, 8i3XY4, 8i3X2Y3 are generated, and radicals to which Si% Bond I4. A high-quality film with a low localized level density and sufficiently terminated with X or Y can be obtained.

In addition, the linear non-logenated silicon compound of the general formula is
Two or more types may be used in combination, but in this case, the expected film properties of each compound are averaged to obtain properties of about 9 or properties that are synergistically improved.

Next, imparting thermal energy to the silicon compound gas introduced into the deposition chamber includes a Joule heat generating element;
This is carried out using high frequency heating means or the like.

Examples of the Joule heat generating element include heaters such as heating wires and heating plates, and examples of the high frequency heating means include induction heating and electric heating. To explain the embodiment using the Joule heat generating element, the heater is brought into contact with or close to the back surface of the support to heat the support surface by conduction.The raw material gas near the l-1 surface is thermally excited and decomposed, and the decomposition products are transferred to the support. Deposit on the surface.

Alternatively, it is also possible to place the heater close to the surface of the support.

Hereinafter, the method of the present invention will be explained in detail with reference to FIG.

FIG. 1 is a schematic diagram of a deposited film forming apparatus for forming a functional film such as a 5-8i photoconductive film, semiconductor film, or insulating film on a support.

Formation of the deposited film takes place inside the deposition chamber 1.

Reference numeral 3 placed inside the deposition chamber 1 is a support base on which a support is placed.

Reference numeral 4 denotes a heater for heating the support, and power is supplied to the heater 4 through a conductive wire 5. A gas introduction pipe for introducing a-8i raw material gas and gases such as carrier gas used as needed into the deposition chamber 1 is connected to the deposition chamber 1 .

The other end of this gas introduction pipe 17 is connected to a gas supply source 9, 10, 11, 12 for supplying the raw material gas and gases such as carrier gas used as necessary. Corresponding flow meters 15-1.15-2.15-3.15-4 are used to measure the flow rate of each gas flowing out towards the deposition chamber 1 from the gas supply sources 9, 10° 11.12.
Branched gas introduction pipe 17-1.17-2.1 corresponding to
7-3.17-4. 70- each
Pulp 14-1.14-2.14-3 before and after the meter
, 14-4.16-1.16-2.16-3.16-4
are provided, and by adjusting these pulps a predetermined flow rate of gas can be supplied. 13-1゜13-2.1
3-3.13-4 is a pressure meter, which is used to measure the pressure on the high pressure side of the corresponding flow meter.

The gases that have passed through the flow meters are mixed and introduced into the deposition chamber 1 under reduced pressure by an exhaust device (not shown). In addition, the pressure meter 18 measures the total pressure in the case of mixed gas.

A gas exhaust pipe 20 is connected to the deposition chamber 1 in order to reduce the pressure inside the deposition chamber 1 and to exhaust the introduced gas.

The other end of the gas exhaust pipe is connected to an exhaust device (not shown).

In the present invention, the number of gas supply sources 9, 10, 11, 12 can be increased or decreased as appropriate.

However, if a single raw material gas is used, one gas supply source is sufficient. However, when two types of raw material gases are mixed and used, or when a single raw material gas (catalyst gas, carrier gas, etc.) is mixed, two or more are required.

Note that some raw materials do not turn into gas at room temperature and remain liquid, so when using liquid raw materials, a vaporizer (not shown) is installed. There are two types of vaporizers: those that utilize heating and boiling, and those that pass a carrier gas through a liquid raw material.

The source gas obtained by vaporization is introduced into the deposition chamber 1 through a flow meter.

Using the apparatus shown in FIG. 1 and the method of the present invention, a deposited film consisting of a-3i can be formed in the following manner.

First, the support body 2 is set on the support stand 3 in the deposition chamber 1.

Various types of supports 2 can be used depending on the purpose of the deposited film formed. Examples of materials that can form the support include NtCl, stainless steel, A/, Cr, Mo, and Au for the conductive support.

Nb% Metals such as Ta, V, Ti, Pt, and Pd are alloys of cholera; semiconductors such as 8i and Qe are used for semiconductive supports; and polyester, polyethylene, and polycarbonate are used for electrically insulating supports. , cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride,
Examples include synthetic resins such as polystyrene and polyamide, glass, ceramics, and paper. The shape and size of the support 2 are determined as appropriate depending on the intended use.

In particular, in the method of the present invention, the temperature of the support is 150°C.
Since the temperature can be relatively low at around 300°C, it is possible to use materials with low heat resistance that cannot be applied to conventional glow discharge deposition methods or thermal energy deposition methods. It is now possible to use other supports.

After the support 2 is placed on the support stand 3 in the deposition chamber 1 in this manner, the air in the deposition chamber is exhausted through the gas exhaust pipe 20 by an exhaust device (not shown) to reduce the pressure. The atmospheric pressure in the deposition chamber under reduced pressure is less than 5 X 10-5 Torr, preferably 10
-6 Torr or less is desirable.

When an electric heater 4 is used as the thermal energy applying means, after the pressure inside the deposition chamber 1 is reduced, the heater 4 is energized to heat the support 3 to a predetermined temperature. The temperature of the support at this time is 150 to 300°C, preferably 20°C.
The temperature is 0 to 250°C.

As described above, since the support temperature is relatively low in the method of the present invention, glow discharge deposition method, 8iH4, Si
.

Next, the valves 14-1 and 16-1 of the supply source 9 in which gases of the raw material compounds (one or more) for forming the a-8i film mentioned above are stored are opened, and the raw material gases are deposited. Room 1
Send it inside.

At this time, the flow rate is adjusted while being measured by the corresponding flow meter 15-1. Usually, the flow rate of raw material gas is 10 to I00
0SCCM, the preferred range is 20 to 5008 CCM.

The pressure of the source gas in the deposition chamber 1 is 10-2 to 100 Torr.
r, preferably maintained in the range of 10-2 to 1 Torr.

In this way, thermal energy is imparted to the raw material gas flowing near the surface of the support 20, promoting thermal excitation and thermal decomposition, and a-8i, which is a product, is deposited on the support.

As mentioned above, the raw material gas used in the method of the present invention is easily excited and decomposed by thermal energy.
A high film forming rate of about 5 to 50 A/sec can be obtained. a
Decomposition products other than -di and undecomposed surplus raw material gas are discharged through the gas exhaust pipe 20, while new raw material gas is continuously supplied through the gas introduction pipe 17; ITIL.

In the method of the present invention, thermal energy is used as excitation energy, but since the application is not a high amount of heat but a low amount of heat, the energy is always applied uniformly to a predetermined space occupied by the raw material gas to be provided. can.

There is no effect of high-power discharge on the deposited film during the formation process, as observed in the glow discharge deposition method. The formation of the deposited film continues while maintaining the temperature.

In this way, a-8i[ is formed on the support 2, and a
When the desired film thickness of -8i is obtained, the application of thermal energy from the heater 4 is stopped, and the pulp 14-1.
16-1 is closed and the supply of raw material gas is stopped. a-8i
The thickness of the film is appropriately selected depending on the intended use of the nine-a-Ji film to be formed.

Next, after the gas in the deposition chamber is removed by driving an exhaust device (not shown), the pulp 21 is opened when the support and the deposited film have reached room temperature, and the atmosphere is gradually introduced into the deposition chamber. The pressure is returned to normal and the support on which the a-8i film is formed is taken out.

The 9a-8i film thus formed on the support by the method of the present invention is an a-8i film with excellent uniformity of electrical and optical properties and stability of quality.

In the example of the method of the present invention described above, the deposited film was formed under reduced pressure, but the present invention is not limited to this, and the method of the present invention can be performed under normal pressure, depending on the gK. It can also be carried out under pressure.

According to the method of the present invention as described above, thermal energy with a low calorific value is used as excitation energy, and a source gas that is easily excited and decomposed by nuclear thermal energy is used. It has become possible to form an a-8i deposited film at a high energy level, and it has become possible to form an a-8i deposited film with excellent uniformity of electrical and optical properties and stability of quality. Therefore, in the method of the present invention, supports made of materials with low heat resistance that cannot be applied to conventional glow discharge deposition methods or conventional thermal energy deposition methods can be used. This makes it possible to save energy consumption, which requires high-temperature heating.

A specific example of the present invention is shown below.

Example 1 An a-8i deposited film was formed using the above exemplary compound (1), (2), (7) or (8) as the linear (chain) 10-genide silicon compound of the above general formula using the apparatus shown in the drawing. .

First, a conductive film substrate (manufactured by Corning, +705
9) on the support stand 2, and use the exhaust device to remove the deposition chamber 1.
The inside was evacuated and the pressure was reduced to 10-6 Torr. The support temperature was set at 220°C, and the silicon halide compound, which was in a gaseous state, was heated at 1l, 108cc, and hydrogen gas was heated at 40°C.
SCCM is introduced into the deposition chamber at a flow rate, and the atmospheric pressure in the chamber is brought to 0.
A 2-J3i film with a thickness of 4000 Å was formed while maintaining the pressure at 1 Torr.

The film formation rate was 30 A/sec.

For comparison, an a-8i film was formed in the same manner using 5t2H6. The film formation rate was 10 A/sec.

Next, each obtained a-8i film sample was placed in a vapor deposition tank and 1
After pulling to O-6Tb rr, vacuum W 10-5 Tor
r.

150 OA of M was deposited at a deposition rate of 20 A/sec, and a comb-shaped M gap electrode (length 250 μ, width 5 m
), the photocurrent (AM 1゜100 mW/am2) and dark current were measured with an applied voltage of 10V, and the ratio σp/σd of photoconductivity σp and dark conductivity σd was determined, and a- 8
i membrane was evaluated. The results are shown in Table 1.

Table 1 shows that the a-3ill according to the present invention has improved σP and σP/σd compared to the conventional one even at a low substrate temperature.

Example 2 The substrate was a polyimide substrate, the support temperature was set at 250° C., and the exemplified compounds (12) and (13) were used as the chain halogenated silicon compounds of the general formula.

An a-Si film was formed in the same manner as in Example 1, except that (15) was used, and σP and σP/σd were determined.

The results are shown in Table 2.

Table 2 [Effects of the Invention] According to the present invention, a high quality silicon deposited film can be formed at a low substrate temperature and at a high film formation rate. Moreover, even when the film to be formed has a wide area and is thick, uniform electrical and optical characteristics can be obtained and quality stability can be ensured, which is an unprecedented and exceptional effect. In addition, it saves energy because it does not require high-temperature heating of the substrate, it can form a film even on substrates with poor heat resistance, it shortens the process by low-temperature processing, and it is easy to use raw materials. It can be synthesized, is inexpensive, has excellent stability, and has the advantage of being less dangerous in handling.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an example of a deposited film forming apparatus used in the method of the present invention. 1: Deposition chamber 2, 21: Support 3: Support 4: Heater 5: Conductor 6-1.6-2.6-3: Gas flow 9, 10.11.12 = Gas supply source 13-1. 13-2.3-3.13-4.18: Pressure meter 14-1.14-2.14-3.14-4゜16
-1.16-2.16-3.16-4,21: Valve 15-1.15-2.15-3.15-4: Flow meter 17.17-1.17-2.17-3. 17-4:
Effect of Gas Inlet Pipe Act 2o: Gas Exhaust Pipe Applicant Canon Co., Ltd.

Claims (1)

[Claims] In the chamber containing the substrate, the general formula: S+nXmYz (wherein, X and Y are different halogen atoms, and n is 1 to
6, m and l are each an integer of 1 or more, m
+J=2n+2. ) A method for forming a deposited film, which comprises forming a gaseous atmosphere of a chain silicon halide compound represented by () and hydrogen, and applying thermal energy to these compounds to form a deposited film containing silicon on the substrate. .